add my_order page
order should reference with user, not event
add pay operation
improve performance
add cancel order
cleanup user_order_controller_spec
remove script/rails
hide generate_pay_link_by_order
log canceled time
Merge pull request #502 from jasl/cleanup_rails3_legacy

去掉不再使用的script/rails
Merge pull request #500 from jasl/my_orders

我的订单
Merge pull request #501 from jasl/cancel_order

用户取消订单
Add gem jbuilder.
Move place order logic to models.

Utilize ActiveRecord validation to verify the user input.
Simplify orders controller.

- Use model nested attributes and validation.
- Move place order to model.
- Add error handling to concern HasApiResponse